<p>问答题</p>
<div *ngIf="!editable">
  <p>{{question.title}}</p>
  <input placeholder="请输入你的问题" class="form-control" [(ngModel)]="question.title">
</div>
<div *ngIf="editable && isEditing">
  <input placeholder="请输入你的问题" class="form-control" [(ngModel)]="question.title">
  <div class="btns">
    <button (click)="onSave()" class="btn">保存</button>
    <button (click)="onCancel()" class="btn">取消</button>
  </div>
</div>
<div *ngIf="editable && !isEditing">
  <p>{{question.title}}</p>
  <div class="btns">
    <button (click)="onEdit()" class="btn">编辑</button>
    <button (click)="onDelete()" class="btn">删除</button>
  </div>
</div>